1. Field of the Invention
This invention is concerned with a method of producing a borated alkyl aromatic polyol. More particularly, it relates to a method of producing a borated alkyl aromatic polyol used in lubricating oil formulations to reduce oxidation, wear, and deposits in internal combustion engines.
2. Description of the Relevant Art
Wear and deposits limit the useful life of automobile and truck engines. Thus, there is a great need to find lubricants that reduce the oxidation, wear, and deposits in the engine, thus increasing the lifetime of the engine.
U.S. Pat. No. 2,795,548 discloses the use of lubricating oil compositions containing a borated alkyl catechol. The oil compositions are useful in the crankcase of an internal combustion engine in order to reduce oxidation of the oil and corrosion and wear of the metal parts of the engine.
Borated alkyl catechols are conventionally prepared via alkylation of catechol with an olefin, followed by boration of the alkyl catechol product with boric acid or boric anhydride (see, for example, U.S. Pat. No. 4,629,578). Hereinafter this will be referred to as the "forward process". This procedure produces borated products containing both monoalkyl and dialkyl catechols; however, the superior antioxidant properties of the monoalkyl catechols make them more desirable products. To enhance the production of monoalkyl products, a large excess of catechol, the most expensive reactant in the process, is needed in the forward process. Unfortunately, this excess catechol must be recovered and recycled to make the process economical.